Possible Battery Pack?


13 posts
by DJ Charlie » Sat Jan 12, 2013 12:03 am
Hi all. Got my Pi up and running, and it's fantastic. BUT, I'm really looking for a battery to make it a bit more portable.

Would the Rayovac Back-Up Charger work? Or would I be better off looking for something else? I'm not looking for a LONG runtime, but something where I can just unplug from the wall temporarily and move to another location.

Rayovac's website for the Charger in question: http://www.rayovac.com/Products/Recharg ... phone.aspx
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by Jim JKla » Sat Jan 12, 2013 12:07 am
There have been loads of battery questions but this appears to be the first sensible one, there should be a pack that would last the ten minutes it would take to swich supplies, or to cover a break in supply caused by a standby generator change over.
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by cyrano » Sat Jan 12, 2013 12:16 am
DJ Charlie wrote:I'm not looking for a LONG runtime, but something where I can just unplug from the wall temporarily and move to another location.


It might work well for that. The only mention about capacity is that it'll charge an 800 mAh battery in 3 hours. But how were you planning on transferring power?
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by DJ Charlie » Sat Jan 12, 2013 12:30 am
cyrano wrote:It might work well for that. The only mention about capacity is that it'll charge an 800 mAh battery in 3 hours. But how were you planning on transferring power?


I was thinking plug the Pi into it, and plug it into the wall adapter. A friend of mine suggested this similar but "beefier" one on Amazon: http://www.amazon.com/Anker%C2%AE-Astro ... 7758011_18

Would that be better, or am I just blue-sky designing?
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by gragib » Sat Jan 12, 2013 12:36 am
You can use any battery pack made for cellphones that charge over microUSB. I use 1 made by Nokia because I've had it for like 2 years now. I've seen similar units made by other cellphone manufacturers and accessory manufacturers.

The battery I mentioned above (DC-11K) has a capacity of 1500mAh; the Raspberry Pi under full load consumes about 850mAh, so this battery should be able to power it for a little less than 2 hours at full load, and for much longer at lower loads.
Last edited by gragib on Sat Jan 12, 2013 12:42 am, edited 1 time in total.
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by DJ Charlie » Sat Jan 12, 2013 12:40 am
gragib wrote:You can use any battery pack made for cellphones that charge over microUSB. I use 1 made by Nokia because I've had it for like 2 years now. I've seen similar units made by other cellphone manufacturers and accessory manufacturers.


But can it be hooked up as I described in my reply to cyrano? That's what's really important to me. :)
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by gragib » Sat Jan 12, 2013 12:48 am
DJ Charlie wrote:But can it be hooked up as I described in my reply to cyrano? That's what's really important to me. :)
Yes, it'll work, but your battery is going to be plugged in to the Raspberry Pi all the time. If you remove the battery pack, the Raspberry Pi will power down (unless you want to do some hacks).
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by efflandt » Sat Jan 12, 2013 12:50 am
Theoretically with 800 mAh it should power a Pi for around an hour, but it does not say what its power output is in mA. Also it does not say if it does "pass through", to charge it an power a device at the same time (unlikely). So you would likely need need 2 ways to connect power to the Pi (micro-USB and through correct GIO pins) in order to switch from AC to battery and back to AC.

Also from some of the comments on that site, not sure how durable that battery pack is. Although, their little USB Wall Charger with folding plug works great for the Pi (rated 1 A and provides over 4.9 V at T1/T2). I have not tested their Universal USB Car Charger with a Pi yet, but it is rated 2 A (did charge a phone with it).

I have a more expensive Mophie 4000 mAh battery pack that specifically says it does NOT do pass through (cannot charge and use it at same time). However, it is rated up to 2.1 A output and will power a Pi with wireless keyboard/mousepad and mini-WiFi for 7.5 hrs at a stable 4.82 V T1/T2.
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by gragib » Sat Jan 12, 2013 12:57 am
If you have a more recent Raspberry Pi (with 0Ω polyfuses or no polyfuse on the USB ports), you can plug a battery into the USB port to backfeed power, unplug the microUSB charger, move your Pi, plug in the microUSB charger again, and then remove the battery.
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by DJ Charlie » Sat Jan 12, 2013 2:51 am
gragib wrote:If you have a more recent Raspberry Pi (with 0Ω polyfuses or no polyfuse on the USB ports), you can plug a battery into the USB port to backfeed power, unplug the microUSB charger, move your Pi, plug in the microUSB charger again, and then remove the battery.


Yes, but I'd rather not have to go fiddling with wires like that once this case is finished. :) I'd like to "set it and forget it," hence the question about using it in a pass-thru configuration.
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by gragib » Sat Jan 12, 2013 3:06 am
If you can find a backup battery with pass-through feature, it'll work well and fine. For the product linked in the original post, I don't know if it supports pass-through.
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by Jim JKla » Sat Jan 12, 2013 7:29 am
If you do find a solution you test it and it works. Report back you may not be the only person that could find the feature useful. ;)
Noob is not derogatory the noob is just the lower end of the noob--geek spectrum being a noob is just your first step towards being an uber-geek ;)

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by DJ Charlie » Sat Jan 12, 2013 10:48 am
Jim JKla wrote:If you do find a solution you test it and it works. Report back you may not be the only person that could find the feature useful. ;)


But of course! I'll probably go ahead and buy the cheap one this coming week, and if it works, get the bigger one later.
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